This is just dumb. But here's a caveat, remember that no touchdown for unsportsmanlike conduct that the NCAA enacted a few years ago? How many times has that been used? Furthermore, how many times has it needed to have been used? Hopefully, this goes the same way--and maybe that was what their intention was: to use an ejection as a deterrence for not hitting high.
There's just one problem--you have the time to consciously think about whether you should celebrate your way into the end zone. You don't (more times than not) have the time to adjust yourself to hit lower on the player and avoid the helmet to helmet hit. Whenever helmet-to-helmet hits have occurred with malice (a la Arkansas-Vanderbilt) the violator was ejected.
So now we're going to start ejecting players for reacting how any human would in an extremely short period of time (AKA not being able to adjust)?
The players know the consequences of the sport, and I'm sure most of them do ALL they can to avoid concussing another player, even if he is on the other team. The research done and ongoing has made everyone very aware of the dangers of brain injuries. Keep making safer helmets--but don't punish players for doing something they can't.